Adjustable folded dipole



Dec. 29, 1964 YOSHIO FUJINO ADJUSTABLE FOLDED DIPOLE 2 Sheets-Sheet 1 Filed July 3, 1962 INVENTOR. yOSH/O FuJ/A o YOSHIO FUJINO ADJUSTABLE FOLDED DIPOLE Dec. 29, 1964 2 Sheets-Sheet 2 Filed July 3, 1962 mvmoa 534/0 FuJ/wo A OEY United States Patent 3,163,863 ADJUSTABLE FOLDED DIPOLE Yoshio Fnjino, Kansai Televi Kogyo K.K., 1751-14 Aza-Kamiumegatani, Nishi-tarumi cho, Tammi-kn, Kobe, Japan Filed July. 3, 1%2, Ser. No. 207,194 Claims priority, application Japan Dec. 29, 1961 8 Claims. (Cl. 343-752) This invention relates to an antenna for radio and television reception, and more specifically concerns a new antenna of improved compact design that may be readily tuned to different wave lengths and which is particularly useful in connection with receiving devices operating on ultra-short ranges.

- A-large variety of different types of antennas commercially available are adapted to serve specific requirements of receiving devices. It has been found, however, particularly in the field of indoor antennas, that improved performance generally required the inclusion of large antenna members and extensions, which are awkward and require considerable space. On the other hand, past efforts to develop more compact designs usually resulted in reduced performance, and adjustment to the reception of a variety of wave lengths became difficult,

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Patented Dec. 29, 1964 antenna in combination with improved flexible, U-shaped This invention has as one of its objectives the provi 1 s-ion of an efiicient indoor antenna for short-wave devices which takes up a minimum of space and which is light and easily transported.

Another objective of this invention resides in the provision of a short-Wave antenna which is easily tuned to a selected frequency and will hold the adjustment until.

tuned to another frequency.

7 A further objective of this particular invention resides in the provision of an improved organization and arrangement of antenna components wherein'the receiving elements may be adjusted simultaneously for maximum reception at a specific wave length.

A still further objective of thi invention entails the provision of a smaller indoor antenna chara'cterizedby a relatively simple design and structure which maybe easily mass-produced at very low cost.

A further objective of this invention resides in the provision of an improved adjustable antenna that is readily adaptable for use over 'a wide rangeof frequencies.

The above and additional objectives and advantages will become more apparent from the following description and drawings forming part of this application.

' In the drawings:

FIG. 1 is a perspective view of the embodiment of this invention. v

FIG. 2 is a cross-sectional illustration showing all internal details of the antenna shown in FIG. 1.

FIG. 3 is an enlarged perspective view of the upper portion of the antenna showing the contacts of the antenna lead connected to both of the end portions of the antenna arms.

- circuit provided with an alternate knob for the antenna.

Broadly, this invention contemplates the provision of an ultra short-wave antenna requiring'considerably less support and the other end-slidably engaging channels within the support, and extending outwardly therefrom in parallel relationship for attachment of a knob or'handle/ Such an arrangement facilitates adjustment of the antenna to a position afiording the best reception for a selected wave length by increasing or decreasing the length of the arcuatereceiving members extending from the antenna support.

To adjust'the frequency of the antenna, the knob or handle is pushed toward the support attached thereto, to expand the flexible members outwardly and away from the supporting base and thereby decrease the frequency. Conversely, when the knob is pulled upwardly away from the support, the length of the arcuate receiving member is shortened, thereby effecting normally increased efliciency in shorter wave length ranges.

In addition to the high efficiency obtained by this antenna, thesimplicity of its design, and the practicality of its operation, it is marked by a pleasing appearance and by a compactness which make this antenna extremely useful, especially for indoor operations.

Referring now to the drawings and specifically to FIG. 1, the supporting member 10 of the antenna is stabilized by and secured to a hollow metal base plate 11 having open lateral sides and an opening in the rear where the connecting cable 12 enters the base. The base plate is relatively heavy in relationship to the structure mounted thereon to stabilize the 'apparaus. This is especially important while the receiving members are extended completely. 'The base plate is prefera'bly made out of a metal, while the supporting structure of the antenna could be constructed of a lighter mate rial such as durable plastic or similar material, providing insulation for the antenna members secured thereto space than known antennas, and one which may be easily and manually tuned over a relatively Wide frequency range.

These advantages and objectives are attained through a novel and improved design of a main support for an and carried therein. The upright supporting member 10 has two spaced'parallel plane surfaces, while the outer periphery describes a symmetrical vase-like configuration with outwardly extending supporting brackets 13 and 14 on the uppermost portion and similar brackets 23 and 24 at the lowermost portion.

The upper brackets 13 and 14 each carry one leg of the U-shaped receiving members 15 and 16, the latter being secured by means of screws 17 and 18 extending through brackets 13 and 14 and receiving members 15 and'16 and threadably engaging square plates 19and 20 to securely fasten the receiving members to the brackets of the supporting base.

These flexible receiving members are preferably made of a highly flexible steel tape, such as is used in conventional retractable tape measures and might be plated with a coating of nickel or chrome to prevent'oxidation of to keep the tape from becoming recumbent when extended beyond the configuration of the arc prescribed. The flexible receiving; members 15 a d 16 extend away from the supporting base in opposite directions, prescribing semi-circular arcs 21 and 22 respectively. The lower or return legs enter the support 10 through channels within the support which open in the ends of brackets 23 and 24.

There are three separate channels within the support which are insulated fromeach other. Channels 25 and 26 have side openings 15 and 16 m the ends: of supporting brackets 23 and Z4 and extend inwardly describing an upwardly curved course leading to individual openings in the top'surface of the support. A third channel 12' 39 7. extends vertically between channels 25 and 26 and carries the cable 12. A magnified cross section of the guiding channels within the support is provided by FIG. which isa cross section taken at the line-55'from1FIG. 2. The return. legs of the .UV-shaped. receiving members 15 and 16 are, slidab ly carried in the channels 25' and 26 with the, ends of. these. extending vertically and, parallel. to each other beyond the top of the support. These free. endsof the receiving members are secured to each other bya bolt 28. anda nut 29. within the knob 27, providing. the necessary contact therebetween. V

The knob 27 facilitates manualv control. of the lengthof the legs of the U-shaped receiving antenna. members with the weight of, the knob counterbalancing. the tension exerted by these members so as to retain the. arcs inanyselected position, which willnotbe displaced by vibratory or other external forces.

A better insight into the functional elements of this antenna is provided by FIG. 2. When downward pressure. isexerted on the operating knob 27,. thesteel tapes are forced downwardly within the channels-15" and 16' pro vided'within the supporting member: and emerge on opposite sides of the suppont,,increasing the lower legs of the U-shaped members, while the other ends-of the tape remain fixedly secured tothe brackets 19 and 20..

Referring now toFIG. 6, the insulated antenna lead 12 enters-the'base through an opening 32 in thebase and extends upwardly through channel 12 "'within the sup port- 10; The ends 30- and 31 of'thislead emerge from an. opening near the topof the support 10 where the stripped leads are soldered or otherwise secured to the plates 19' and: 20 as may be readily observed'in't-he' enlarged illustration of FIG. 3.

Although any convenient means for mounting the support on'the hollow metal base may be utilized,.FIG-.-2 shows one procedure which utilizes-an intenlocking. tongue and grooveiarrangement ata33 'on one side of the support, while the opposite sidev of, that; support is provided witha spring-operated locking; arrangement, comprising a spring. 34* secured to the. supportIand extending. downwardly. in a recess-35* to engagetcooperating-means on the base. In this manner, the support IO- and the base port including a pair of channels extending therethrough and slidably receiving the other legs of said' receiving elements with the ends of the last said (legs extending from said channels, means carried by the ends of said other iegs for movement toward and away from said support to adjustthe length of said elements, and means on said antenna for attachment of an antenna cable thereto;

2. An antenna according to claim 1 wherein saidflexible receiving elements areformedof steel tape having a slight cross-sectional curvature for additional stiffness and resilience.

3. An antenna according to claim 1 wherein said knob V is weightedto' counterbalance the pressureexertedagainst saidknob by the resilience 'of said' receiving elements;

4. An antenna; according to claim 1' wherein a. coil connects two corresponding ends. of said receiving element's, and said antenna cable meansis connected to the other correspondingends of said' elements;

5. An antenna according to claim 1 wherein each of said channels extending through said" support has one; opening, on, one side of said support, saidjchannel's'leadingj inwardly from their respective, openings, curving up-. wardly within said. support, andv terminating in' the top surface of said supportand eachoflsaid channels slidably carrying alegof saidreceiving element. 7

6. An antenna accordingto. claim 1', wherein the support has insulating, characteristics and hassa vertical,

f 7 channelcarrying a-conneoting cable.

7. An antenna for receiving devices, comprising. a stabilizing base, an uprightsupport.securedto said'base, at least two flexible, U-shaped'receiving ele'mentscarried by said support. with saidrreceiving elements. extending from opposite surfaces: ofsaid support, eachv element having 1 1 can be easily disengaged by exerting. pressure; on'the the two antenna members one to the. otherwand thereby lowers the frequency range of the antennai The knob is secured in position. enclosing the coil'41 and'the ends of the antenna elements by means of a bolt 42: a

The latter modification in combination-with thetantenna described makes this invention an efiicient andmost versa-e tile apparatus havinga relatively widelfrequencyirange. The design-is alsocharacterized by: its simplicity; compactness and relatively low cost. a

While only certain: embodiments of this invention have been illustrated and described in .the application, it i is apparent thatialterations and modifications may be made without departing from the truescopeiand 'spirit'thereof.

What is olaimedis: t

1. An antenna comprising'asupport; U'-shaped flexible receiving elements each having one leg secured to said one leg securedto opposingsurfacesofsaid support, and being insulated from each otherby said support, said support having channels. therein, said channelseach having arropening on-saidopposingnsu1faces and in a plane defined by said legs-secured to said support, said channels extendingfrom: said openingsinwardly and curving upwardly to openings in a. surface intermediate to said side surfaces, the other leg-of each of said U-shaped receiving-elements:being slidably carried each within one of said -channels,- the free ends of the last said legs extending at equal length andsimparallelrelationship each from the said last-openings, anelectrical connection between said ends, a-nonconductive knob securing said ends one to 'the.other,.1said support ineludi-ngtanother channel extending vertically through said support and an insulated connect ng: cable therein, saidv cable including two termirials, said terminals being electrically connected to said first legs andnsaidt cable; providingmeans. .for attachment to a receiving device.

8. Anaantennaaaccordingv to claim 7 wherein: theifirst said electrical connection comprises a coil connected between said endsiof. said receiving elements :and disposed within said knob.

References. (Zifed inathe'file' of this patent UNITED STATES IPATENTS 2,565,661 Lidz- Aug. 28, i 2,569,810 Hamel et al Oct. 2, 1951 Ehr1ich. Nov. 13., 1951 OTHER REFERENCES adi a Television News; May. 1949, page 163,: 

1. AN ANTENNA COMPRISING A SUPPORT, U-SHAPED FLEXIBLE RECEIVING ELEMENTS EACH HAVING ONE LEG SECURED TO SAID SUPPORT AND EXTENDING OUTWARDLY THEREFROM, SAID SUPPORT INCLUDING A PAIR OF CHANNELS EXTENING THERETHROUGH AND SLIDABLY RECEIVING THE OTHER LEGS OF SAID RECEIVING ELEMENTS WITH THE ENDS OF THE LAST SAID LEGS EXTENDING FROM SAID CHANNELS, MEANS CARRIED BY THE ENDS OF SAID OTHER LEGS FOR MOVEMENT TOWARD AND AWAY FROM SAID 